The pharmacokinetics of mycophenolate mofetil (MMF) in liver transplant recipients may change because of pharmacokinetic interactions with coadministered immunosuppressants or because changes in the enterohepatic anatomy may affect biotransformation of MMF to mycophenolic acid (MPA) and enterohepatic recirculation of MPA through the hydrolysis of mycophenolate acid glucuronide to MPA in the gut. In the latter case, the choice of formulation (oral versus intravenous) could have important clinical implications. We randomized liver transplant patients (n ϭ 60) to standard (10-15 ng/mL) or reduced (5-8 ng/mL) trough levels of tacrolimus plus intravenous MMF followed by oral MMF (1 g twice daily) with corticosteroids. Pharmacokinetic sampling was performed after the last intravenous MMF dose, after the first oral MMF dose, and at selected times over 52 weeks. The efficacy and safety of the 2 regimens were also assessed. Twenty-eight and 27 patients in the tacrolimus standard-dose and reduced-dose groups, respectively, were evaluated. No significant differences between the tacrolimus standard-dose and reduced-dose groups were seen in dose-normalized MPA values of the time to the maximum plasma concentration (1.25 versus 1.28 hours), the maximum plasma concentration (15.5 Ϯ 7.93 versus 13.6 Ϯ 7.03 g/mL), or the area under the concentration-time curve from 0 to 12 hours (AUC 0-12 ; 53.0 Ϯ 20.6 versus 43.8 Ϯ 15.5 g h/mL) at week Abbreviations: AUC, area under the concentration-time curve; AUC 0-12h , area under the concentration-time curve from 0 to 12 hours; AUC last , area under the concentration-time curve from 0 hours to the last measurable concentration; BPAR, biopsy-proven acute rejection; C max , maximum plasma concentration; C min , mean of the predose and 12-hour plasma concentrations (or trough concentration when a 12-hour sample was unavailable); IV, intravenous; MMF, mycophenolate mofetil; MPA, mycophenolic acid; MPAG, mycophenolic acid glucuronide; N/A, not available; SD, standard deviation; T max , time to the maximum plasma concentration.